1. Field of the Invention
This invention relates to an intake cooling system for an outboard motor equipped with a V-type engine.
2. Background of the Invention
Outboard motor engines get extremely hot during operation due to the heat generated by the engine and the trapping of the heat by the engine cover. This heat buildup decreases the air intake efficiency of the intake passageways. By equipping the engines with an intake cooling system that prevents a temperature increase in the intake manifold, the intake filling efficiency is improved and the engine output is increased.
For example, intake cooling systems have been described before, in Japanese patent applications (Kokai H6-123225 and Japan Kokai H6-123228), as intake cooling systems for an outboard motor equipped with a four-cycle engine. Both of the aforementioned applications address intake cooling systems of outboard motors that have engines with cylinders arranged in line, and therefore are not adaptable to a V-type engine, which has a different arrangement of cylinders and an intake manifold.
It is accordingly a primary object of the invention to provide an intake cooling system for a V-type outboard engine. This is achieved by providing a fluid-cooling passageway exclusively for an engine intake manifold. The cooling fluid will normally be water. Thus, the preferred embodiment of the invention will be described using water as the cooling fluid. In the present invention, the primary object is achieved by providing a water cooling system having a water sleeve, using water that has cooled the intake manifold also for cooling the main oil reservoir inside the engine.
In accordance with the invention, there is an intake cooling system for use in an outboard motor equipped with a V-type engine. The V-type engine has cylinder heads, cylinder blocks, and a crankcase, and is arranged with a crankshaft that is almost perpendicular to the joint face of the crankcase and the cylinder blocks.
The cooling fluid will normally be water. Thus, the preferred embodiment of the invention will be described using water as the cooling fluid. In the present invention, the primary object is achieved by providing an intake cooling system having a water-cooling passageway positioned in an intake manifold and used for cooling the manifold. The intake cooling system also has a water sleeve for cooling a main oil reservoir located inside the engine. The water sleeve is positioned next to this main oil reservoir and uses water that has cooled the intake manifold to also cool lubricating oil in the oil resrevoir. While this embodiment uses water to cool the engine, any suitable fluid may be used. Thus, the term water and fluid are interchangeable.
In another embodiment of the present invention, the intake cooling system is used in an outboard motor equipped with a V-type engine, which has cylinder heads, cylinder blocks, and a crankcase, and forms a V-bank between left and right integral cylinder blocks (by arranging the cylinder blocks in a V-shape, as viewed from above). The outboard motor is equipped with an intake system in this V-bank and an exhaust system on the outside left and right of the V-bank while being also having the crankshaft almost perpendicular to the joint face of the crankcase and the cylinder blocks.
The intake cooling system has passageways positioned in an intake manifold. The system also has a water-cooling passageway, exclusively for use in the intake manifold, arranged in a roughly V-shaped valley and formed by bending the intake passageways toward the left and right cylinder heads, in opposite directions from each other. This embodiment further has a water sleeve for cooling lubricating oil in a main oil reservoir. The water sleeve is positioned next to this main oil reservoir, and water that has cooled the intake manifold is led to the water sleeve.
In another embodiment, the intake cooling system of a V-type engine outboard motor further includes an intake manifold thermostat that opens and closes according to the lubricating oil temperature. The thermostat is positioned upstream of the water-cooling passageway; thus, the water does not flow to the water-cooling passageway until the lubricating oil reaches a predetermined temperature.
Another embodiment of the present invention has an oil filter linked to the main oil reservoir. An intake manifold thermostat is positioned between the main oil reservoir and the oil filter.
In another embodiment of the intake cooling system of a V-type engine outboard motor the system includes a water-cooling intake hole, exclusively for the intake manifold. The water cooling intake hole is positioned near an oil passageway linking the main oil reservoir and the oil filter. In this embodiment, the water-cooling passageway extends from the water-cooling intake hole and is positioned along the oil passageway.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.